Production of vitamin containing pasteurized milk of low racterial content



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Way 72 GfivQI ES v %1Hmrnm R. R. GRAVES ITAMIN CONTAINING PASTEURIZED MILK OF LOW BACTERIAL CONTENT Filed Oct. 14, 1927 PRODUCTION OF V March 31, 1931.

ll Market milk is usual Patented Mar. 31, 1931 UNITED STATES BOY R. GRAVES, OI IENSDI'GTON, mm!) INDUCTION O1 VITAMIN CONTAINING PASTEUBIZED m 01' 106W normal:

CONTENT Application med October 14, 1827. 'lerial Io. 888,188.

' This invention relates 'to roduction of vitamin containing pasteurize milk of low a bacterial content; and it comprises mechanically milking a cow under aseptic conditions, a transmitting the milk from the udder to a pasteurizing a paratus without access of air via a 'receptac e wherein said milk is, stored for a time at body temperature to permit ggrmicidal action, pasteurization of the milk ing at a temperature advantageously around 145 to165 F.; all as more fully hereinafter set forth and as claimed.

The reduction of sanitary milk at eco nomica prices is of s ecial public importance.

roduced as pasteurized milk or as certi ed milk. Pasteurized milk is milk which is generally collected from a number of farms, taken to a central point and there treated in special pasteurizing aparatus. Usually the cows are milked directinto open receptacles and the milk is transfzirred to large receptacles and these are transported by wagon to a railroad center and shipped thence to a pasteurizing plant.

Pasteurization is not done, as a rule, until some hours after the milking and prior to.

pasteurization the milk has opportunity to come into contact with air under several different conditions, including the milking,

transferring from the milk pail and delivery to pasteurizing apparatus. Certified milk is used for most part by invalids, infants and others desiring a fresh milk that is of especially low bacterial content. Certified milk is raw milk produced under unusually sanitary conditions. Special costly barns within which the herds are housed are necessary, there is a large amountof labor necessary for washing and grooming of the cows, frequent washing of the barns, the laundering of clothing of the employees, the medical examination of the employees, etc., all resulting in increasing the cost of roduction and therefore the sales price 0 certified milk. But even with all the precautions taken, the raw milk may still possibly be infected by some animal or man borne disease, such as tubercu- 1 losis, typhoid, septic sore throat, fever resulting from B. abortua, etc.

50 The present invention produces high grade tent market milk in a manner different from either of these ways. Milk may contain bacteria of many different kinds,but they can be classified in the usual three main classes, aerobic,

tion by manure and other decagng matter are also. aerobic. The latter cteria are largely spore hearing. In the present invention I suppress the growth of aerobic bacteria and prevent their presence to a very large exmaintainin the milk under vacuum conditions with exc usion of external. air from first to last; that is from the cows udder to the milk bottle. With exclusion and an pression of this class of bacteria the usei'ul effect of pasteurization is much enhanced. Pasteurization can usually be relied upon to kill 98 per cent or so of the viable bacteria; present and it of course makes considerable difference how many bacteria are originally present since some 2 per cent of the number present are apt to survive pasteurization; the 2 percent representing of course the more hardy types; which are mostly aerobes. For further restrictin the amount of bacteria present in the mil at the time of pasteurization I utilize another expedient. Milk as drawn has a certain amount of germicidal ower when maintained at body temperature. hat is, if the milk be drawn with a certain bacterial content and be stored at bodytemperature the number of variable bacteria decreases progressively during a certain period of time. Ordinarily, thegreatest decrease is during the first hour after being drawn; that is a curve showing the bacterial content of milk thus stored reaches its lowest point within sixty minutes from the time the milk is drawn from the udder.

In accordance with the present invention I milk cows under aseptic conditions, using mechanical milkin apparatus and usin precautions to see t at no bloody milk is r-awn, and I deliver the milk while at body temperature to an apparatus, referably a heat-insulated tank, in which t e milk is maintained at or near the body temperature for a period of an hour. While as stated the number of bacteria reaches its minimum in the first hour after bein drawn there is no substantial increase wit in the next fifteen to twenty' minutes. All these operations are done without access of air to the milk at an time. Maintaining the milk at about 98 for about an hour allows me to take advantage of the germicidal action described, and in so doing at this early stage of the operation I materially reduce the bacterial count so that in the subsequent stages of my operation .I asteurize a milk having an unusually low bacterial content. After the milk has been maintained for about an hour in the heat-insulated tank, I then asteurize it, (advantageously in the same tan at temperatures around 145 to 165 F., and then immediately deliver the so pasteurized milk ast a cooler and directly into a bottling machine of closed type. At no time from the milking of the cows to the final bottling do I allow the milk to come into contact with the air; thereby precluding accidental contamination with aerobic bacteria and maintaining conditions under which such as are present are prevented from multiply- In the accompanying drawing I have shown apparatus useful in the performance of my process.

Fig. 1 is in section with part of the milking barn and pasteurizing house shown in elevation and Fig. 2 is a sectional elevation of the measurin receptacle.

he barn is divided into a number of stalls 1 usually six on a side. The end one only is shown. Adjacent the end stall is a pump house 2 divided by a artition 3 from a pasteurizing room 4. Ad} acent the pasteurizing room are a cooler and bottling machine (hereinafter referred to). They may be located in the asteurizing room 4, the arran ement here s own being diagrammatic. n the barn the cows are milked with machines of the releaser, relay or New Zealand type. The machine shown comprises a vacuum and pulsation pump 5 operated by motor 6 and having a pulsation line 7 and a vacuum line 8, the vacuum line leading past the usual sanitary trap 9. Leadingfrom the pulsation and vacuum pipes 8 and 7 are lines 9 and 10 respectively connected to the milking machine 11. Operation of this type of device is well known, the pulsation and vacuum effecting milking. Leading from the milking machine is a line 12 delivering the milk to any usual type of measurin receptacle that shown as 13 is provided wit a glass gage '14. The receptacle shown has a fine screen under glass at its entrance so that a lance will detect gargety or bloody. milk; f such should be seen the milk is removed from the receptacle without entering the sanitary pipe line and the pasteurizer. Leading from the measuring receptacle is a valved line 15 in communi cation with the vacuum line 16, this in turn leading to the vacuum tanks A and B of the pasteurizing apparatus. Tanks A and B may be filled alternately through the valved connections 17 and 18 and may be emptied alternately through the valved connections 19, 20 and 21. The line 21 leads to the coolin device 22 from which cooled or refrigerated milk is conducted by pipe 23 to diagrammatically shown bottling ap aratus 24. A vacuum is maintained in tanks A and B by means of the main pump 5 having a connection 25 leading to tanks A and B through the valved branch 26.

In one way of operating my process, using the apparatus described, cows to be milked are groomed and taken in units of six, or other desirable number, to the special milking barn. Here they are milked by the milking device which draws the milk by vacuum from the cows udder into the sanitary pi e line 16 located on the shed framework a ove the cows. Between the line 16 and the milking apparatus 11 is the receptacle 13 which serves for measuring the quantity of milk delivered by each cow. The asteurizing tanks A and B are heat-insulated and the milk is delivered to either one of them,,according to the setting of the valves on lines 17 and 18. When one is full the other is being filled. The milk is held in either one of these tanks A or B at about the temperature it is delivered from the cow, around 98 F. Ordinarily I do not desire to hold the milk in either of these tanks for more than an hour before pasteurizing for the reasons hereinbefore stated. When the milk has been held in the tank for from thirty minutes to an hour, part of this time being consumed in filling, the temperature is then raised to 140-165 F., depending upon whether the holdin or the flash process is used. If the holdin process is used the milk is maintained un er a temperature of 145 F. for about thirty minutes. If the flash process is used, the milk is flashed at about 165 F. The milk is then drawn from either of the tanks ast the cooler 22 and from the cooler into the covered bottling. machine 24.

The two pasteurizing tanks A and B may each hold from 50 to 75 gallons. When one tank has been drawn full of milk the new incoming milk will be switched to the other tank and this second tank will be filled While the first tank is being pasteurized. The two tanks thus alternate in filling and pasteurizing until the milking is completed. With'a six-cow milking unit in operation, approximately 50 gallons of milk will be drawn per hour. As stated, the milk in each of the tanks A and B should be maintained atbody temperature before pasteurizing and cooling. Usually an hour is suflicient for this purpose. This maintenance of the milk at body temmeans perature for a relatively short period is advanta eous. While the bacterial content of the milk delivered to the pasteurizer directly from a cow is low, still milk from healthy cows usually contains some bacteria. But milk from normally healthy cows also contains some bactericidal constituents which destroy many of the bacteria commonly found in milk. This destruction of bacteria is termed germicidal action. The duration of such germicidal action varies with the temperature of the milk and the length of time elapsed after milking. The closer the temperature of the milk is kept to bodyheat the greater will be the decrease of bacteria for a short period of time immediately following milking. Therefore the holding of the milk in the pasteurizing tank before asteurization. less than an hour following milking not only prevents any increase of bacteria in the milk, but, because of the ermicidal action described, results in a deci ed decrease.

The function of the vacuum in the described process is twofold; b exclusion of air contamination with air orne bacteria is prevented and unfavorable conditions for the life of aerobic bacteria are created. Incidentally, with the line sealed for vacuum mechanical contamination is also prevented. While I have described preservation of a vacuum onl up to and including pasteurizing, it is a vantageous to hold the vacuum during bottling if bottled milk is to be provided. In so doing, vacuum exists at all times on the milk after it leaves the udder and until it is sealed in bottles. When vacuum sealing in bottles is used, pasteurization can of course be after bottlin Another and very great advantage of the present invention is t e preservation of the natural vitamins of the milk. In pasteurizin milk in' the presence of air, vitamin C is estroyed. By pastcurizing in the absence of air, as in the present invention it survives. In the absence of air the heat of asteurization also exercises less detrimenta action on vitamins A and B.

What I claim is 1. In the economical production of high ade market milk having a high vitamin and low bacterial content the process which comprises milking a cow and transferring the milk to a pasteurizing apparatus under vacuum conditions without release of the vacuum during the transfer, the milk allowed to remain under vacuum conditions at body temperature for from thirty to sixty minutes, prior to pasteurization.

2. In the economical production of high grade market milk having a high vitamin and low bacterial content the process which comprises milking a cow by an apparatus of the vacuum type, transmittmg the milk without breaking the vacuum to a storage chamber, allowing it to remain in the storage chamber at substantially bod tem tune, for a time suficient to eflect a dimi riu tion in the bacteria present and thereafter pasteuriaing under vacuum.

3. -In the economical production of and low bacterial content the procem which com rises milking a cow by an a paratus of t e vacuum type, transmitting he milk without breaking the vacuum to a storage chamber, allowing it to remain in the storage chamber at substantially body temperature, for a time suflicient to efiect a diminution-in the bacteria present, thereafter Rasteurizing under vacuum, coolirig and bottling under vacuum conditions; without access of air to the milk at an time during its progress between udder an bottle.

4. In the economical production of high grade market milk, the rocess which comprises milking the cow, a lowing the milk to remain without substantial rise in temperature for a time amounting to from 30 to 60 minutes, to efl'ect a diminution in the bacteria present, cooling the milk and packaging it; all under vacuum conditions.

In testimony whereof, I have hereunto affixed m signature.

y BOY B. GRAVES.

grade market milk having a high sat- 

